What is the ruling on supplicating with the aforementioned wording, and what is the meaning of "By You, I repel him at his throat, and I seek refuge in You from his evil"?

This supplication is not authentically attributed to the Prophet, peace be upon him; rather, it was narrated from Ja'far al-Sadiq, as mentioned by Ibn Abi al-Dunya and Ibn Asakir. There is no impediment to supplicating with it. A supplication with a similar meaning to the phrase "and through You, I repel him, and I seek refuge in You from his evil" has been narrated from the Prophet, peace be upon him: "O Allah, we place You in front of them [against their throats], and we seek refuge in You from their evils." This means that a servant asks Allah to protect him from his enemies and to avert their evils from him.